Bladder tumore have so far been unique in being chemically induced and having cross reacting cell mediated immunity. These antigens may be fetal or viral in origin or they may be due to a urine factor. We plan to induce bladder tumors with different carcinogens with and without urine present to determine the effect of the urine upon the antigenic nature of these tumors. Using these same tumors we hope to develop a marker that can be used to identify bladder tumor cells in culture and distinguish them from possible fibroblastic overgrowth.